It was one thing you didn't have to buy a ticket for; on the other hand only one American in a million had the unarguable right to enter.

The 191 holders of the Medal of Honor, commonly called the Congressional Medal of Honor though the Congress only recognizes and does not originate the honor, entered the Capital Hilton at 6 p.m. yesterday for a banquet and ball honored by a late-evening appearance by President Reagan, honoring him in turn by receiving him.

The president had been to 10 other inaugural events, he said, "but this one is special," adding that the medalists and other veterans present had much to do with preserving a free government. He spoke only a few seconds and danced a minute with Mrs. Reagan, both of them looking fresh and buoyant.

There were 750 people for supper arranged by the American Legion, with other service outfits pitching in for the dance. Each medalist was invited to bring a guest. Dressed fit to kill. There were wives 65 years old with red hair in tight curls, and young filmy women with super-vitamin eyelashes (granddaughters, possibly) and teen-aged boys peering about uneasily but hoping everybody would think they were fierce, and all of them were hanging on to some hero.

"Here comes the mobile corps," a fellow cried as a batch of men in wheelchairs entered. Black and white; some were young and handsome and could have run an Irish pub, while others could have worked in a hardware store in Harrisburg and some could have been philosophers.

Washington crowds look the same, allowing for accidents of costume, in the Safeway or at State, and you never see that look in London or Paris. They have the American look, innocent and hard, but if you grin at any one of them you get the 18-tooth smile known through the world.

Emotion ran high, of course, and was the more subdued for that. The American colors were presented and everyone scowled. The anthem was sung and everybody glowered. Clamp the jaw and you make it okay.

Anywhere you looked, however, your neighbor was a hero; maybe only once, but even once, with the Medal, is passport to the American pantheon.

Clomping down the stairs before the ball began was Beryl Newman of Remnick, Va., with a bandage just above the ears and tight around his head. Didn't dance.

"I been wearing it I don't know 20 years or something. I was blown off a tank. Right, in Europe. I got this brain concussion and I get headaches. I felt sorry for those guys in the Pacific. They didn't have tanks. "

You don't get the medal, however, for being blown off a tank, but for heroism beyond the mere endurance of fate. The medal says what the guy may not.

A medalist doesn't have to be right. He only had to be one American in a million when the fire was on. Later he could talk it out, or drink it out or sleep it out or laugh it out, but under fire something singular and beyond ordinary reach was touched by each of them for the sake of home.

Newman said when he got out of service he had a hundred bucks and never yet was rich.

"Well," said his wife, patting her stomach and looking at his, "you gotta say we never starved."

The little group laughed. Never starved, no sir. Even when things were hard he had enough.